Age / Sex : /

Age / Sex : 52/F
Chief complaint : bilateral lower scapular area protrusion (Rt: 6 years, Lt: 3 years)

elastofibroma dorsi

Discussion

Findings:
- Ill-defined heterogeneous mass (approximately 9.6x3.2x7.4cm) between the serratus anterior muscle and posterior rib - T1 low and T2 low SI (similar with surrrounding muscle) with interlaced high SI on T1WI - Mild heterogeneous enhancement

Differential Diagnosis:
 neurofibroma, cicatrical fibroma, malignant fibrous histiocytoma

Diagnosis: Elastofibroma dorsi

Discussion:
Introduction
- benign fibroelastic lesion of unknown cause
- considered as a pseudotumor, reactive in nature (not neoplastic), and attributable to mechanical friction of the scapula against the ribs during heavy manual labor
- probably arises from periosteal fibroblasts with deranged elastic fibrillogenesis
- an occupational history of manual labor and weight lift
- most commonly found in the sub- or infrascapular regions of the chest wall
- periscapsular in 99% of reported cases, and are often bilateral (10-66%)
- several times more common in women than men
- develop in middle-aged and elderly persons
Site : between the chest wall and inferior scapular (most characteristic)
- synchronous infraolecranon lesions (16%)
- hand, foot, greater trochanter, ischial tuberosity, deltoid region, temporal bulbar conjunctiva, and cervical epidural space
CT - a poorly defined, inhomogeneous soft-tissue mass with attenuation similar to that of skeletal muscle, containing linear streaks of fat attenuation
MR - relatively low signal intensity (similar to muscle) on T1- and T2- weighted images.
      - interlaced fat is seen as strands of high signal intensity within these hypointense lesions   
      - variable enhancement, which may reflect increased vascularity of the lesion

References:
- AJR 1992;159:575-579 - Cancer 1982;50:1794-1805